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Wed, 12 Aug 2026 11:51:56 +0000 (GMT) Received: from li-4c4c4544-004d-4810-8043-b7c04f423534.ibm.com.com (unknown [9.61.9.29]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Wed, 12 Aug 2026 11:51:56 +0000 (GMT) From: Anthony Krowiak To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: jjherne@linux.ibm.com, borntraeger@de.ibm.com, mjrosato@linux.ibm.com, pasic@linux.ibm.com, alex@shazbot.org, kwankhede@nvidia.com, fiuczy@linux.ibm.com, pbonzini@redhat.com, frankja@linux.ibm.com, imbrenda@linux.ibm.com, agordeev@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, stable@vger.kernel.org Subject: [PATCH v3 6/9] s390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap Date: Wed, 12 Aug 2026 07:51:36 -0400 Message-ID: <20260812115139.576303-7-akrowiak@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260812115139.576303-1-akrowiak@linux.ibm.com> References: <20260812115139.576303-1-akrowiak@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEyMDA5MyBTYWx0ZWRfX1vecvEeq5/1c u5P04XBfEkjKqZmOUyjYF8krWU+c6jYy8BOU08+s8Mox758MBWPeemq+OYMLvLIUg8Bfx+4uKal l4fi8C89hXpyYAM+jLO2uOOUl9kxcmvjN50By7fGw2DrHmca6mO18bN8fiaTwAmn9XTNjN333Nd IR+zDbUaL8qJ07QkKSZV9QC5WfQohd2W94g9BC7hdjF8ydqz3xfuMkU/K2uSD5e2XNCf6/xTTuT 2wVpFWY+7twUv8IzXU579gt+RqnY+MsNCc6ysBvhAZ0cB9EyTC4eQzLvpZhyShObfDFVRjhcnzK ea4qmZhsc08rtom8mOWhGCD4H9PFR+4oeo270HbwIFtFIX6Omp3o8YYwgOqVhhhTA4qisqWrPRy U7L82KCow9bwDJ+94G8xxgDdBHzv+fwl7574GrQL1ReqAArYEiWQN4RX2SeuQUITHbMjDQzBl9I L6e59DkQT5nrXhtbnvA== X-Proofpoint-ORIG-GUID: XLV49F9vP9erkG8foBpX0-4lgouwECxs X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDA5MyBTYWx0ZWRfX9x/U1f195wnw M4ipFidgy+LSK3BvegMt/VfVZPlN+DBn2xvFYcOPfKlfDDh11AehXyB6+hbTwS1PW1KROvyAU5Q U7zY/FrSYN2aAwjxS0LRW7XukClwoWc= X-Authority-Analysis: v=2.4 cv=IfK3n2qa c=1 sm=1 tr=0 ts=6a7c5e61 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=_H5xUuJxPEx76qSOziYA:9 X-Proofpoint-GUID: XLV49F9vP9erkG8foBpX0-4lgouwECxs X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-12_03,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 impostorscore=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 adultscore=0 malwarescore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608120093 The DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap on the stack without zero-initializing it. In vfio_ap_mdev_hot_plug_cfg(), the vfio_ap_mdev_filter_matrix() function is only called to initialize and populate apm_filtered if either filter_adapters or filter_domains is true. If the hot plug configuration change only adds control domains (meaning filter_cdoms is true, but filter_adapters and filter_domains are both false), vfio_ap_mdev_filter_matrix() is bypassed. Consequently, apm_filtered is passed to reset_queues_for_apids() with uninitialized stack garbage. This can cause reset_queues_for_apids() to interpret arbitrary stack garbage bits as valid APIDs to reset, potentially performing unintended guest hardware queue resets. Fix this by zero-initializing the apm_filtered bitmap at the beginning of vfio_ap_mdev_hot_plug_cfg() using bitmap_zero(). Fixes: eeb386aeb5b7c ("s390/vfio-ap: handle config changed and scan complete notification") Cc: stable@vger.kernel.org Signed-off-by: Anthony Krowiak Reviewed-by: Matthew Rosato --- drivers/s390/crypto/vfio_ap_ops.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index b6d0c988cc81..cdc9bf5c5e53 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -2840,6 +2840,8 @@ static void vfio_ap_mdev_hot_plug_cfg(struct ap_matrix_mdev *matrix_mdev) DECLARE_BITMAP(apm_filtered, AP_DEVICES); bool filter_domains, filter_adapters, filter_cdoms, do_hotplug = false; + bitmap_zero(apm_filtered, AP_DEVICES); + filter_adapters = bitmap_intersects(matrix_mdev->matrix.apm, matrix_mdev->apm_add, AP_DEVICES); filter_domains = bitmap_intersects(matrix_mdev->matrix.aqm, -- 2.53.0